It is clear what US President Donald Trump and North Korean leader Kim Jong-un should seek at their second summit later this month: an agreement that is entirely different from the one they made at their first meeting.

The vagueness of the agreement Trump and Kim made in Singapore in June resulted in a lack of progress in efforts to denuclearize the North, which largely tainted the historic significance of the first-ever meeting between the leaders of the former war adversaries.

But expectations -- though not wild optimism -- should rise as the two sides’ decision to hold a second Trump-Kim summit in Vietnam on Feb. 27-28 itself may well mean they both want to move beyond what was agreed to in Singapore.

Indeed, the two sides made little progress in each of the three key areas of their Singapore accord: improvement of bilateral relations, establishment of a lasting peace on the Korean Peninsula and complete denuclearization of the peninsula.

The greatest stumbling block was their confrontation over which side should take the first steps. The US wanted Pyongyang to declare its nuclear bombs, materials and related facilities first, and take other convincing steps toward denuclearization. The North wanted Washington to reward it for actions it had already taken, including a halt to nuclear and missile tests and the destruction of a nuclear testing site and missile engine-testing facility, by providing a guarantee of its security and sanctions relief.

In the meantime, news and intelligence reports keep pointing to signs of the North continuing its nuclear and missile activities, bolstering skeptics’ doubts as to the regime’s willingness to abide by its disarmament commitment.

What’s been good is that unlike in the past, the North Korean side did not go back to the brinkmanship it often resorted to when its demands were not met. Trump has also maintained optimism about talks with the North, emphasizing his good relationship with Kim.

In line with the two leaders’ wish to keep the talks from falling apart, the two sides had been making efforts to set up a second meeting between Trump and Kim to break the deadlock in a “top-down” manner.

US Secretary of State Mike Pompeo visited Pyongyang in October, his fourth visit to the North Korean capital. Trump also received Pompeo’s North Korean counterpart, Kim Yong-chol, in the White House last month, which was followed by tripartite talks among senior diplomats from the two Koreas and the US in Stockholm, Sweden.

Then Stephen Biegun, the US nuclear envoy, flew to Pyongyang on Wednesday, almost at the same time as Trump disclosed the dates for his second summit with Kim in his State of the Union address in Washington.

Biegun’s discussions with his counterpart, former North Korean ambassador to Spain Kim Hyok-chol, and other senior officials will set the direction for the second Trump-Kim meeting.

According to media reports and experts, steps that may be taken by the North Korean side included dismantlement of its core nuclear facilities in Yongbyon and destruction of more missile-related sites. What’s noteworthy is that North Korean officials told Pompeo in October they were ready to abandon both plutonium and uranium facilities. It marked the first time the North had admitted to its uranium-based weapons program.

Mentioned as steps that may be taken by the US side are the establishment of a liaison office and provision of humanitarian aid to the North. The key factor, of course, will be the declaration of the end of the Korean War, which Pyongyang regards as a means to guarantee its security, and relief on sanctions imposed over its nuclear and missile provocations.

The Biegun-Kim Hyok-chol talks in Pyongyang and follow-up meetings between the two sides will tackle all those issues in pursuit of a package deal to be endorsed by Trump and Kim at their Vietnam meeting.

The US side should be reminded that without concrete action plans for the final, fully verified denuclearization of the North, any agreement would be dismissed by the world as one that would only satisfy the vaingloriousness of Trump, who is keen on claiming a major foreign policy feat.

After all, what’s essential for ending the threat from the North’s weapons of mass destruction is to get a real, enforceable denuclearization road map based on a full list of nuclear and missile-related materials and facilities. This should not be compromised under any circumstances.